Two days after viewers learned how Jack died, Tuesday's hour revealed the devastating aftermath for Rebecca and the Big Three in the days following the sudden loss of their beloved husband and father. Titled "The Car," the episode revealed the story behind Jack's favorite tree, what happened to his younger brother, Nicky, and why Jack wanted his remains "outside."

"I feel like Rebecca really honored his wishes by having his service outside, and I don't think that she was really present at the ceremony. I think she was going through the motions," Mandy Moore said during the This Is Us after-show. "The conversation with Dr. K is what spurred the idea of, 'I know what we're going to do. 'I know where we're going to go. We're going to have our own moment as a family of four to really talk about Jack and what he meant to all of us. This is going to be the first day of the rest of our lives.'"

Speaking more specifically to Rebecca's tear-jerking heart-to-heart with Dr. K, the doctor who helped her birth Kevin and Kate, the 33-year-old actress spoke about the poignancy of that conversation.

"She's at that point in the grieving process where it's total unacceptance: 'I cannot be the parent that I want to be without him. We were in this together,'" Moore said. "Everything great that happened to this family was because of his doing, and now that he's gone, I think she's like, 'I don’t know how to be a parent to these teenagers.'"

"Seeing herself through [Dr. K's] eyes is what jump-starts her back into reality that, you know what, it's not going to be easy and it's going to be completely different, but she'll figure this out," she continued. "She's going to be the best mother she possibly can be to be these kids."

Moore also recalled shooting Tuesday's episode, saying that she felt like she was having an out-of-body experience, especially when it came time to film Jack's funeral service

"As we were shooting [the] episode, I just kept thinking in my mind for those moments, like, I am floating. I am so unconnected and disconnected from anything and everything around me, including my kids,"she said. "I think she just couldn't find any ground."

Added Milo Ventimiglia, who told ET on Monday he chose not to be present for Jack's funeral: "I don't think anyone is ready for a loss of that magnitude, especially with how Jack and Rebecca were and are as a couple. They were one. It was just them. The two of them felt like one of those couples that, when they got old, one would pass and then moments later, the other one would too."

The 40-year-old actor offered hope that audiences could see hints of what could have been had Jack not died in January 1998 at the age of 53, alluding to possible dream sequences and the recent twist that the show will also go years into the future.

"There's an opportunity to even dream a little further forward -- the moments possibly that we didn't get that we could've gotten had this man lived on a little longer," Ventimiglia teased.

As for what awaits the final three episodes of the season now that the mystery of Jack's death has been tied up, executive producer Ken Olin said that he hopes viewers use Tuesday's episode as acknowledgment that it's "OK for them to move on."

"Our storytelling is going to remain as ambitious," he promised. "There are still a lot of things that need to be discovered about Jack’s life.”